A semiconductor wafer has become thin to a thickness of the order of tens of micrometers, and it is necessary to handle the semiconductor wafer so as to avoid external forces, such as bending, warpage, a physical impact, or the like, as much as possible during the course of processing or transportation. In a dicing process for dicing a semiconductor wafer into individual semiconductor chips, adoption of a mechanical dicing method using a circular blade, or the like, has hitherto been common. However, a method called plasma dicing which enables lessening of damage to a wafer resulting from mechanical dicing has recently been proposed. Plasma dicing is a technique for: forming in a resist film boundary grooves which partition semiconductor elements from each other, by means of exposure-transfer, through a mask, of a dicing pattern onto the resist film formed on one surface of a semiconductor wafer, thereby forming, in a resist film, boundary grooves while partition semiconductor elements off from each other; and eliminating the uncovered surface of the semiconductor wafer in the boundary grooves by means of plasma etching, to thus dice the semiconductor wafer into individual semiconductor chips along the boundary grooves.
There has also been put forth a method for radiating a laser beam onto areas corresponding to boundary grooves-which will be formed by means of a dicing pattern-instead of forming a dicing pattern through exposure-transfer (Patent Document 1). Since this method obviates the necessity for an expensive exposure transfer system, plasma dicing can be performed at low cost.
[Patent Document 1] JP-A-2005-191039